Advanced Photonics in Urology 2025

Urethral stricture is a condition causing urethral narrowing due to chronic inflammation or scarring, affecting men over 55. It has the potential to cause complications such as urinary tract infections and kidney problems. Treatment methods include urethral dilatation, incision, or anastomosis. We propose a new treatment method, near-infrared laser-based cylindrical photothermal ablation, to minimize recurrence and treatment area. The 1470 nm laser for numerical simulations in porcine liver and urethra tissue environments. Ex vivo urethra experiments were conducted using the same laser irradiation conditions. The results show that the 15 W for 5 s condition could ablate the mucosa area of the stricture site in the urethra.

This study aims to investigate the mechanism of the stimulative effects of wavelength-dependent laser exposure on prostate cancer. The current findings showed that, depending on the wavelength, photo-modulation effects may stimulate tumor growth in the tumor microenvironment. In addition, the molecular mechanism of modulatory effects was examined through the signaling pathway and genetic factors. Further studies will establish the laser irradiation methods to minimize tumor stimulation and confirm the tumor-stimulating effect of the laser irradiation under various parameters against urological cancer.

Photobiomodulation (PBM) is a treatment that uses light of 600-1000 nm wavelength at 5-500 mW to enhance cell proliferation and tissue regeneration. Energy density is an essential parameter influencing various cellular responses, including cell proliferation and apoptosis [1]. PBM has been utilized to treat the side effects of cancer radiation therapy. However, PBM has the potential to stimulate the growth and metastasis of cancer. Metastasis of tumor cells represents significant difficulties for diagnosis and management [2]. Therefore, the current study aims to evaluate the PBM effects on tumor growth under various energy densities. B16F10 tumor-bearing mice were irradiated with an 808 nm laser at 5, 10, and 50 J/cm2 and observed for 10 days. In vivo test showed that the group exposed to 5 J/cm2 had the largest increase in tumor volumes, while the smallest increase was observed in the control group (p < 0.05). In addition, the 808 nm laser irradiation at 5 J/cm2 resulted in higher protein expression on VEGF and HIF-1α compared to control (p < 0.05). The current study demonstrated that PBM with an 808 nm laser significantly could promote tumor growth at 5 J/cm2.

Clinical application of photodynamic therapy (PDT) for upper tract urothelial carcinoma (UTUC) requires to set of irradiation conditions based on the light distribution of the therapeutic light in the tissue. In this study, we evaluated the effects of irradiation conditions and tissue characteristics on PDT of UTUC in terms of light penetration depth and dose volume histogram (DVH). The simulation results shows that scattering coefficient and tube inner diameter of the ureter tissue had a large influence on the light penetration depth, while the influence of scattering coefficient was small. For DVH, the influence of tumor thickness in addition to absorption coefficient and tube inner diameter was significant. The influence of individual differences could be evaluated for the index design of irradiation conditions in PDT for UTUC.

The flashlamp-pumped CTH:YAG or Ho:YAG (Cr3+, Tm3+, Ho3+) triple-doped yttrium aluminum garnet laser has been the benchmark laser console for lithotripsy for over twenty years. The transient pressure field profile of the vapor bubbles produced by laser pulses provides key insight for understanding kidney stone ablation, retropulsion, and damage control of nearby acoustic shock-sensitive devices. This study aims to evaluate the transient pressure field profile of the vapor bubbles in water produced by the laser pulse of a Ho:YAG laser. A hydrophone measures the transient pressure field from the laser lithotripsy fiber tip at 0, 90, and ~180 degrees.

Thulium fiber lasers (TFL) were introduced a few years ago for clinical use in urolithiasis. In comparison to Ho:YAG lasers, they offer the advantage of better dusting results and lower retropulsion, but show limitations in fragmentation. We investigate the influence of the beam profile on ablation efficiency using a TFL with 750W peak power by a series of measurements with annular and Gaussian beam profiles of varying diameters using different types of artificial stones. In addition, the effect of the laser wavelength (and thus the water absorption) on the ablation is investigated by comparison with the Ho:YAG laser and different artificial stones.

For some urological applications such as lithotripsy and Benign Prostate Hyperplasia (BPH) treatment, high average power and high pulse energy laser emission in the 2 um spectral region is required. Often, this requires the usage of multiple laser resonators combined to overcome the thermal effects of the CTH:YAG gain media. Beam combining methods can be complicated and difficult to align. Our novel beam combining method, with the use of several enabling technologies, results in a physically and optically compact design capable of reaching high average power. We report on the output of a beam combined laser with 4 independently operating CTH:YAG resonators lasing on the 2.13 um transition. Each resonator produced approximately 4 J at a repetition rate of 10 Hz, resulting in a combined output of more than 4 J at 40 Hz. We have demonstrated the output of beam combined resonators resulting in an output greater than 120 W through a 600 um fiber at a 40 Hz repetition rate. We have also demonstrated the ability to launch a laser beam with output power of approximately 60 W through a 200 um fiber.

Stress urinary incontinence (SUI) involves involuntary leakage of urine. A sling procedure, which supports urethra, by using artificial mesh. However, the sling procedure causes bleeding and infection in the urethra. The aim of the current study is to develop and evaluate new non-ablative transurethral laser treatment for SUI. Female guinea pigs (GP) were used to develop a SUI animal model. Then, the urethra in the SUI animal model was irradiated with 980 nm laser light at 10 W for 5 s via a balloon-assisted diffusing applicator. The functional and histological evaluations were performed to confirm any structural changes. The functional evaluation showed that the SUI animal model had a leak point pressure (LPP) of less than 60 cmH2O. The histological evaluation exhibited a 20% decrease in urethral muscle and a 30% decrease in the distribution of collagen. The laser treatment group showed an increase in LPP of a 51%, compared to the SUI group. The total urethral thickness from the lumen was increased by a 40%, compared to the SUI group. The current study demonstrated the efficacy profile of the transurethral 980 nm laser treatment in the SUI animal model.

This study presents a deep learning-based computer-aided diagnosis system for automated detection of prostate cancer grades and chronic prostatitis on biparametric MRI. Using a dataset of 1647 biopsy-confirmed findings from 1074 patients, we trained a 3D convolutional neural network based on the nnU-Net architecture. The system achieved high performance in detecting clinically significant prostate cancer, with a lesion-wise partial FROC AUC of 1.94 and a patient-wise ROC AUC of 0.874. Notably, the inclusion of prostatitis as an auxiliary class improved the system's specificity. We also identified optimal b-values for diffusion-weighted imaging and explored a novel data augmentation technique using simulated multi-modal shift. This research demonstrates the potential of deep learning to enhance the interpretation of prostate MRI by simultaneously detecting cancer grades and benign conditions, potentially improving the clinical utility of CAD systems in prostate cancer screening.

Background: Demographic shift in industrial societies leads to increasing numbers of patients presenting with BOO due to locally advanced prostate cancer. As there is currently no guidelines recommendation on technique, we compared intraoperative performance, postoperative outcomes, and safety for palliative (p)TURP and (p)HoLEP. Methods: Retrospective, propensity score-matched analysis of 1,373 and 2,705 men who underwent TURP or HoLEP for LUTS/BOO between 2014 and 2021. Patients were stratified by technique, and groups were compared for perioperative parameters, safety, and short-term functional outcomes. Results: Postoperative symptoms and urodynamic parameters improved irrespective of technique. With significantly increased resection and enucleation times for palliative indication, the benefits of HoLEP remain unchallenged by TURP. For corresponding efficiency parameters, we observed a two-fold higher surgical performance (g/min) for both techniques in patients without prostate cancer. Conclusions: While laser enucleation of the prostate is a safe and effective procedure, pHoLEP offers better surgical performance compared to pTURP.

This study evaluates MRI-guided transurethral ultrasound ablation (TULSA) for localized prostate cancer in 300 patients. TULSA treatments were performed using MRI for planning and real-time guidance, allowing for precise targeting and temperature monitoring. Safety outcomes were favorable, with mainly low-grade complications. Functional outcomes showed preserved erectile function and improved urinary symptoms over time. Oncological control was assessed using PSA, MRI, and biopsy, with a subset of patients requiring salvage therapy or further monitoring. The results demonstrate that TULSA is a safe and effective minimally invasive treatment option for localized prostate cancer, offering the potential for reduced morbidity compared to traditional therapies. This advanced technology combines the benefits of MRI imaging with targeted ultrasound energy delivery, showcasing the potential of image-guided interventions in urological applications.

Objective: To compare learning curves for pulsed thulium laser enucleation of the prostate (ThuLEP) for three surgeons with different levels of surgical experience. Methods: We prospectively analyzed the first 100 consecutive cases of ThuLEP surgery for a very experienced (>1000 previous HoLEPs), an experienced (>100 previous HoLEPs) and an unexperienced surgeon (no HoLEPs), undergoing a structured training program, regarding perioperative parameters, functional outcomes, and safety. Patients were randomized 1:1:1. Results: While postoperative functional outcomes didn’t differ, we report a faster learning curve for experienced surgeons, with the very experienced surgeon learning twice faster than the experienced counterpart. Experienced surgeons reach a plateau twice earlier in enucleation efficiency (g/min) and enucleation time (min), while utilizing half of laser energy (kJ). Significance: Pulsed ThuLEP shows a comparable learning curve to HoLEP for the unexperienced surgeons, when following a structured training program. Switching lasers is safe and feasible for surgeons already experienced in HoLEP.

This study investigates the integration of 3D MRI and clinical data to enhance prostate disease diagnosis. By combining biparametric MR studies with patient demographics and clinical findings, including longitudinal PSA levels, we developed fusion models that significantly improve diagnostic accuracy. Our best-performing model achieved higher ROC-AUC and quadratic weighted Kappa scores compared to image-only or tabular data-only approaches. These results highlight the potential of comprehensive data fusion in computer-aided diagnosis systems for urological applications, offering more precise and personalized diagnostic processes.

Benign Prostatic Hyperplasia (BPH) affects the prostate gland in men, causing urinary symptoms that impact quality of life. This presentation explores the latest advancements in BPH treatment, including minimally invasive procedures and surgical options. The goal is to provide an overview of current and emerging therapies.

Recent scientific studies have supported the importance of measurement of heart rate (HR) and heart rate variability (HRV) related to cardiovascular disease (CVD). CVD is a known risk factor for both lower urinary tract symptoms (LUTS) and overactive bladder (OAB). There is currently no outpatient test to measure HR and HRV to uroflowmetry and detrusor oxygenation during voiding. Objective: To test in an outpatient clinic setting a synchronous, noninvasive measurement of HR and HRV, detrusor activity, and uroflowmetry using optical systems. This study confirm the feasability of this new methodology which can now be used for larger scale clinical diagnostic studies in LUTS.

Bladder cancer (BC) treatment is costly due to high recurrence and revision surgeries. If a resected tumor is diagnosed as high-risk by post-operative histological assessment, revision surgeries are mandatory. We present a fully integrated, clinically compatible SRS imaging device for real-time histological assessment of BC during surgery. We demonstrate excellent agreement between acquired SRS images and classic H&E-stained images. Our device paves the way for classifying BC risk levels, enabling intraoperative therapy stratification. Additionally, our device spans the full Raman spectrum, offering rapid, detailed molecular profiling and potentially reducing reliance on advanced diagnostic tools.

High-tone pelvic floor dysfunction (HTPFD) is a neuromuscular disorder of the pelvic floor characterized by non-relaxing pelvic floor muscles, resulting in voiding and defecatory symptoms, and pelvic pain. There are limited quantitative measures of pelvic floor muscle (PFM) physiology, limiting accurate diagnosis. Near infrared spectroscopy (NIRS) is a non-invasive diagnostic tool for real time measurement of physiologic muscle parameters. Methods: A vaginal NIRS probe measured PFM physiologic changes over the course of five maximum voluntary contractions and one sustained maximum contraction of the PFM. Half-recovery time of hemoglobin difference, HbDiff(½RT) was calculated, a validated oxygen kinetic parameter indicating muscle metabolic function. The aim was to evaluate if differences in HbDiff(½RT) could be detected in women with HTPFD compared to controls. Results: 24 asymptomatic control and 5 women with HTPFD were evaluated. In women with HTPFD there was an absence of desaturation as well as a failure to recover to pre-contraction oxygenation after relaxation. Throughout the pelvic floor HbDiff(½RT) was prolonged in the HTPFD subjects, indicating worsened metabolic function.

Achieving an accurate diagnosis of chronic kidney disease (CKD) is important to ensure individuals receive appropriate intervention as and when needed to optimize clinical outcomes. There is a critical need in finding a reliable non-invasive approach to diagnose CKD. Our study demonstrated that the novel use of machine-learning combined with multispectral autofluorescence imaging of proximal tubule cells (PTCs) exfoliated into the urine has great potential in this setting.

Bacterial infections on Ti bioimplants are a serious problem. Recently, surface coatings with photothermal agent (PA) have recently attracted increased interest. Copper sulfide (CuS) is considered as a promising PA agent in various biomedical uses due to its high photothermal efficiency and ease of fabrication. The poor adhesion of CuS on Ti limits its applications. Hence, this work was aimed to develop a NIR-II (1064 nm) light-triggered CuS-polyetherimide (PEI) coating on Ti with better adhesion and antibacterial properties. A simple wet-chemical and dip coating/casting approach was used to synthesize CuS NPs and the CuS-PEI coating. The antibacterial property was evaluated against S. aureus using the spread plate method. Under NIR-II light irradiation, the photothermal activity of CuS NPs (100 g mL-1, 0.65 W cm-1) and CuS-PEI coated OH-Ti (0.4 W cm-1, 8 min) was optimized with ~89% antibacterial activity. The in vivo study showed no toxicity and >90% antibacterial reduction of CuS-PEI/OH-Ti (at 0.28 W cm-1, 8 min). The study suggests that the NIR-II light-triggered antibacterial efficacy of CuS-PEI/OH-Ti may be a useful strategy to combat bacterial infection of Ti bioimplants.

In this study, we designed a prostate cancer-targeted gold nanoparticle-based photothermal and photodynamic complex (GNR-ICG-FA@PSMA) to increase the specificity of prostate cancer and to simultaneously deliver photothermal therapy (PTT) and photodynamic therapy (PDT) effects. DU145, human prostate cancer cells, were used for in vitro and in vivo tests. The GNR-ICG with laser group showed highly expressed ROS, the highest apoptosis rate, and the lowest cell viability percent. In in vivo test, GNR-ICG-FA@PSMA injected by tail injection reached the cancer within nine hours. In addition, GNRs caused necrosis by increasing the temperature (< 50 ℃) upon laser irradiation, and ICGs caused apoptosis by generating ROS. According to the results, folic acid (FA) and PSMA antibodies enhanced prostate cancer-specific binding. GNR and ICG were responsible for generating photothermal effects and photodynamic effects, respectively. In conclusion, the current study demonstrated the feasibility and usefulness of GNR-ICG-FA@PSMA for targeted photothermal/photodynamic therapy of prostate cancer.

Stress urinary incontinence (SUI) is a urine-leaking condition due to sphincter malfunction. Recently, a balloon-integrated diffusing applicator (DA) with 980 nm laser at 20W showed promising results for SUI treatment by sphincter regeneration. But, large divergence beam from DA can surpass sphincter length (~16 mm) causing unexpected injury. Radial fiber (RF) emits a narrow beam. This study numerically compares laser emission profiles from various angle fiber tips (β) in balloon-integrated RF for SUI treatment by ZEMAX software. 400-µm fibers with β = 74°, 58°, 42° were used to deliver 980 nm laser at 20W. No significant difference was found among output beam widths at balloon surface (~2 mm). Divergence angles (α) of output beam decreased (α = 88°, 59°, 33°) as β decreased (β = 74°, 58°, 42°). Starting beam position relative to tip (d) at balloon surface was affected by α (d = 0, 1, 2 mm for α = 88°, 59°, 33°). Normalized longitudinal intensity peak for β = 74° was higher than those for β = 58°, 42° (10%, 17%). Thus, RF with β = 74° offers more precise control and effective energy for laser treatment of SUI. Future studies will assess RF performance in ex vivo and in vivo.